Two earthquakes, including one given a preliminary magnitude of 4.2 have been recorded in northern Oklahoma.
The U.S. Geological Survey reports the quake struck just before 10:30 p.m. near Stillwater, about 65 miles (105 kilometers) north of Oklahoma City.
The U.S.G.S. reports a second quake of preliminary magnitude 2.8 struck less than 30 minutes later in the same area.
No injuries or significant damage are reported.
Thousands of earthquakes have struck Oklahoma in recent years, many linked to the underground injection of wastewater from oil and natural gas production. State regulators have directed several oil and gas producers to close some injection wells and reduce volumes in others.